[Support] Make sure sys::fs::remove can remove symbolic links and make sure LockFileManager can handle a symbolic link that points nowhere.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204422 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 5 insertions, 8 deletions

diff --git a/lib/Support/LockFileManager.cpp b/lib/Support/LockFileManager.cpp
index ba1047b88a..c8472d8805 100644
--- a/lib/Support/LockFileManager.cpp
+++ b/lib/Support/LockFileManager.cpp
@@ -29,16 +29,13 @@ using namespace llvm;
 /// \returns The process ID of the process that owns this lock file
 Optional<std::pair<std::string, int> >
 LockFileManager::readLockFile(StringRef LockFileName) {
-  // Check whether the lock file exists. If not, clearly there's nothing
-  // to read, so we just return.
-  if (!sys::fs::exists(LockFileName))
-    return None;
-
   // Read the owning host and PID out of the lock file. If it appears that the
   // owning process is dead, the lock file is invalid.
   std::unique_ptr<MemoryBuffer> MB;
-  if (MemoryBuffer::getFile(LockFileName, MB))
+  if (MemoryBuffer::getFile(LockFileName, MB)) {
+    sys::fs::remove(LockFileName);
     return None;
+  }
 
   StringRef Hostname;
   StringRef PIDStr;
diff --git a/lib/Support/Unix/Path.inc b/lib/Support/Unix/Path.inc
index 500b7fecb7..1c91053610 100644
--- a/lib/Support/Unix/Path.inc
+++ b/lib/Support/Unix/Path.inc
@@ -305,7 +305,7 @@ error_code remove(const Twine &path, bool IgnoreNonExisting) {
   StringRef p = path.toNullTerminatedStringRef(path_storage);
 
   struct stat buf;
-  if (stat(p.begin(), &buf) != 0) {
+  if (lstat(p.begin(), &buf) != 0) {
     if (errno != errc::no_such_file_or_directory || !IgnoreNonExisting)
       return error_code(errno, system_category());
     return error_code::success();
@@ -316,7 +316,7 @@ error_code remove(const Twine &path, bool IgnoreNonExisting) {
   // check ensures that what we're trying to erase is a regular file. It
   // effectively prevents LLVM from erasing things like /dev/null, any block
   // special file, or other things that aren't "regular" files.
-  if (!S_ISREG(buf.st_mode) && !S_ISDIR(buf.st_mode))
+  if (!S_ISREG(buf.st_mode) && !S_ISDIR(buf.st_mode) && !S_ISLNK(buf.st_mode))
     return make_error_code(errc::operation_not_permitted);
 
   if (::remove(p.begin()) == -1) {